Ordered versus disordered InGaP layers grown by liquid phase epitaxy

We make a comparative study of the optical and structural characteristics o f two InxGa1-xP (x approximate to 0.5) films nearly lattice matched to GaAs , (here referred to as disordered type 1 sample (S1) and ordered type 2 sam ple (S2)). The films were grown by liquid phase epitaxy (LPE). Photolumines cence (PL) measurements were performed in a wide temperature and exciting p ower density range for different polarization of the emitted radiation alon g the [110] and [110] directions. Observations suggest that the InxGa1-xP l ayer in sample 1 is disordered, as commonly obtained in LPE growth, while i n sample 2 at least a partially spontaneously ordered layer was obtained. M oreover, the energy position of the 20 K PL peak is close to the predicted band gap energy for the InGaP2 material ordered in the CuPt phase. [1].